WSB1-63 2P Miniature Circuit Breaker

A 2P MCB switches and breaks both the line (phase) and neutral conductors of a single-phase circuit in one operation. It is commonly used as a main switch for a single-phase consumer unit, for equipment requiring double-pole isolation (such as heaters, kitchen appliances and EV chargers), and in countries or installations where neutral isolation is required by code.

In a 2P device the phase and neutral poles are mechanically linked, so a fault on either pole trips both together and the toggle operates as one unit. With two separate 1P breakers, tripping one pole does not guarantee the other opens, and a fault on the neutral leg may leave the phase live. The linked trip of a 2P also gives a clear break on both conductors for maintenance.

Like all WSB1-63 breakers, it uses a thermal-magnetic trip unit. The bimetal strip provides inverse-time protection against sustained overload, bending over seconds or minutes depending on how far current exceeds In. The electromagnetic release provides instantaneous short-circuit protection, tripping within milliseconds when current crosses the B/C/D curve threshold.

The WSB1-63 2P is available in B, C and D curves. For ordinary household lighting and sockets with resistive loads, Curve B or C is typical. Curve C is the safer general-purpose choice because it tolerates the small inrush from fluorescent lights, TVs and small pumps that can nuisance-trip a B curve. Choose D only for loads with heavy starting surges such as compressors or large transformers.

It covers standard ratings from 6A up to 63A, including 6A, 10A, 16A, 20A, 25A, 32A, 40A, 50A and 63A. Size In so that it is greater than the design current (Ib = load power ÷ 230V) but no greater than the cable's current-carrying capacity (Iz). For a 230V circuit, a 3kW heater draws about 13 A, so a 16A breaker on 1.5–2.5 mm² cable is typical; a 7kW shower needs a 40A breaker on 6 mm² or larger cable.

It is rated for AC 230V (single-phase, line-to-neutral) at 50/60 Hz, with a 400V rating between the two poles on the 2P construction where used as a double-pole device. It is designed for standard single-phase household and commercial supplies; do not apply DC or voltages above the marked rated voltage.

The breaker snaps onto a standard 35 mm DIN rail inside a suitable distribution board, but the wiring itself should be carried out by a qualified electrician. Connect the incoming line and neutral to the top terminals and the outgoing line and neutral to the bottom terminals, observing the correct polarity, and tighten terminals to the torque in the datasheet. Always isolate and lock off the supply before working inside the board.

If it trips after the circuit has been running for a while, check for overload (too many high-power appliances sharing the circuit) or loose terminals causing heat. If it trips the moment a device starts, the inrush is hitting the magnetic trip — moving from a B curve to a C curve often resolves it. If it trips instantly with nothing plugged in, suspect a short circuit or damaged cable and call an electrician rather than repeatedly resetting.

No. An MCB protects only against overload and short circuit between line and neutral. It does not detect earth leakage current flowing through a person or damp earth path. For shock protection, the MCB must be used upstream or downstream of a residual-current device (RCD/RCBO) selected to match the installation's earth fault conditions.

It is manufactured to IEC 60898-1, the standard for miniature circuit breakers for household and similar low-voltage overcurrent protection, and carries CE marking. Type testing covers thermal and magnetic trip characteristics, short-circuit withstand, endurance and temperature rise. Always verify the specific certificate applies to the exact rating, curve and breaking capacity you order.